I’ve picked up a number of people at different airports recently and was able to wait in front of the doors. I think it depends on how crowded the area is as to how fast you’ll be asked to move on.
I would recommend that both parties have a copy of the layout of the airport and agree to a specific meeting point. Many airports with parking garages have multiple levels of exits and it’s a bitch trying to coordinate this in real time (just went through this). Once you know “where” then when is easier to figure out. the person waiting for the plane to arrive can track the flight on the computer (ex: flight aware) and prestage near the airport waiting to confirm landing. By the time the person gets off the plane and gets to the exit the ride is there and waiting.
Or you can just park in short term parking and wait in the building.